Variable-Refrigerant-Flow Zoning Helps Make Doctor's Dream a Reality

For 32 years, Dr. Byron M. Holm, a family practitioner in Plymouth, Ind., and his wife, Mary, a registered physical therapist, dreamed of a “one-stop” health-care and medical fitness center for wellness promotion, state-of-the-art diagnostic services, and rehabilitation. On July 13, 2007, their dream became reality with the grand opening of LifePlex Health Management Center. The facility encompasses 143,000 sq ft on two floors and includes the Holm Medical Clinic; Fitness Forum; centers for specialty orthopedics, nephrology, cardiac rehabilitation, screening, and diagnostic X-ray; and speech-therapy, diabetes-counseling, and nutritional services. The facility also includes leased office and retail space, a café, a pharmacy, and a day-care center.

A CHANGE IN PLANS

Originally, LifePlex was to employ a modular four-pipe chiller/boiler variable-air-volume system. But after learning about the City Multi variable-refrigerant-flow-zoning (VRFZ) system from Mitsubishi Electric HVAC, Holm asked J.D. McGrath of McGrath Refrigeration of Knox, Ind., to redesign and customize the facility.

Equipped with advanced inverter technology that varies compressor speed to meet changing load requirements in indoor zones, the City Multi system is able to distribute capacity, control temperature in all conditioned spaces, and, in the case of outdoor R2-Series units, simultaneously cool and heat over two pipes.

“When the center was built, the tenants were not all secured,” Paul Quigley of Excelsior Manufacturing & Supply Corp. of Elkhart, Ind., who assisted McGrath with the redesign, said. “We had no idea who would be occupying the space and what their ultimate needs would be, since so many of the areas were originally designed for construction skin load only. The City Multi solution provided us with an extreme amount of flexibility for add-ons, equipment changes and relocations, walls moving, etc. One of our larger skin-load designs ended up as a nephrology care center that needed variable temperature capabilities. Once the design for that was finalized, we had less than 20 days to finalize the design and completely install the system, which wasn't a problem with the City Multi system.”

CONTROL SYSTEM

The LifePlex gymnasium is a modified, open-concept, two-story complex with a complete running track circling the upper level. McGrath and Quigley designed a system that absorbs stratified heat on the upper level and shifts it to lower-level units via energy recovery through the refrigerant in City Multi R2-Series units. Outdoor air is introduced economically via four 1,200-cfm Lossnay energy-recovery ventilators (ERVs), which are tied into the building's comfort-control system.

Other areas, including the aerobics center, the racquetball courts, the fitness center, and several offices, are treated with a combination of one-way and four-way concealed/recessed-cassette indoor units; ductless, wall-mounted indoor units; and various ducted indoor units. The 60,000-sq-ft, two-story, multiservice medical center also was designed with a combination of indoor units integrated with Lossnay ERVs. All 243 tons are controlled with Mitsubishi's TG2000 integrated system software.

CENTRALIZED COMFORT AND CONTROL

G-50A controllers provide access to every unit in the facility from a centralized location. Additionally, some occupants were given simplified controls for fine-tuning, while others were given the ability to control the comfort of their environments via their desktop computers.

TAX CREDITS, DISCOUNTED UTILITY RATES, AND TENANT BILLING

The City Multi technology allowed Holm to obtain a sizeable tax credit and discounted utility rates. Additionally, the G-50A controllers, along with watt-hour meters, allow him to monitor energy use in each zone and bill tenants accordingly.

ENVIRONMENTAL IMPACT

Environmental impact was a critical factor in the design of the LifePlex system.

“Dr. Holm … made it known immediately that we needed to provide his center with an extremely efficient system that runs on very low-wattage electricity, one that would burn no carbon fuels,” Quigley said. “We could not have done better with any other system. This is a very ‘green’ package.”

PERFORMANCE

The City Multi systems at LifePlex were monitored with the outdoor temperature at 96°F and the building fully occupied. Holm's reports show the HVAC systems were running at a cost well below the industry standard.

“In our industry, those numbers are so low, they are no less than stunning,” Quigley said.

Added Holm: “A City Multi R2-Series system … effortlessly handles any and all climate or zone challenges. For example, we have been extremely impressed with the fact that in our medical center, which generates significant heat from radiation and stress tests, City Multi keeps us cool and comfortable. The same great flexibility applies to our aerobic centers (kept at 69°F), our racquetball courts (kept at 68°F), our yoga classroom (set at 72°F), and our college-size basketball court (71°F on the court and 72°F on the overhead track).”

The bottom line, Holm said, is that: “We have had nothing but happy customers who enjoy the comfortable exercise environment the City Multi systems provide. The equipment is already paying dividends, not only in discounted electric rates and energy savings, but in the happiness (wellness) quotient from everyone in our new facility.”